The invention concerns a hydraulic machine with an orbiting displacement element connected unrotatably with an output shaft via an intermediary shaft, the intermediary shaft having at least at one end an external toothing, which engages an internal toothing, which engagement permits a swivel motion of the intermediary shaft.
Such a machine is known from, for instance, U.S. Pat. No. 3,973,880.
Machines of this kind can, for example, be used as motors, pumps or steering units. The function of the output shaft depends on the desired application purpose. When the machine is used as a motor, the motor delivers its mechanical output via the output shaft. When the machine is used as a pump, it is driven by the output shaft. In the case of a steering unit, a steering handwheel can be connected with the output shaft.
In many cases the displacement element is made as a gear, which mates with a second displacement element made as a ring gear. During operation the displacement element does not only perform a pure rotational movement, it also orbits around the axis of the output shaft. An intermediary shaft, also called "dog-bone", is provided to enable the transmission of this rotational movement to the output shaft. This intermediary shaft must permit the required swivel motion.